Learn What Is EPUB File Extension?

Introduction

What is .epub file format – EPUB is a popular open-source file format for e-books, Stand for Electronic Publication . It is an XML based format and encloses the content in XHTML format. It can be easily accessed on any device such as mobile, tablets, computers, etc. It totally free and open standard, which was published by IDPF (International Digital Publishing Forum). EPUB ebook file format consists of a single file that has a file extension .epub. EPUB is the most commonly used open, free e-book format, with popular e-book readers such as Noble and Barnes’s Nook, Apple iOS-powered devices like the iPhone and  iPad, the Sony Reader and more that supports the standard.  Out of which, one of the major eBook reader on the market these days are only Amazon's Kindle that lacks built-in support for the EPUB format. This EPUB file format is totally based on three open standards, i.e.

Open Publication Structure (OPS)

An EPUB file 2.0 uses XHTML 1.1 to make the publication content. It means that ePUB file involves one or more web pages. Even though, users can contain the whole content of a book/newspaper in a single page. In a similar way, with regular web pages, the layout as well as styling is defined by using CSS (cascading style sheets). In EPUB files, a subset (limited series of commands) of CSS2 requirements to be utilized. Most of the new features of CSS3, such as rounded boxes or drop shadows, do not exist yet. For backwards compatibility, a creator can also utilize DTBook instead of XHTML for encoding the content.

Open Packaging Format (OPF)

This part of file format deals with structural information such as Metadata (who is the publisher and author, what is the title, etc.), the manifest (list of all the files that are inside ePUB file) and the table of contents. All these data are embedded by using XML.

Open Container Format (OCF)

EPUB document comprises of a series of files. The OCF defines that how all files end up being packaged into one single container file. zip compression is utilized for this. If you take an EPUB file and change its extension from .epub to .zip then, you can unzip the publication and take a look on all those files.

Recommendation: To change the extension of EPUB file, If it is necessary, so user can use software to export EPUB document to portable PDF.

Font handling

There are two ways for handling fonts in ePUB files:

• Epub file is a collection of web pages therefore; fonts can be mentioned in the CSS.
• Fonts embedding: It is a way by which characters shapes are included in a file. It is
  1. Useful to preserve specific style.
  2. Maintain non-ASCII characters.

Images in EPUB files

The ePUB file format supports the mentioned image file formats:

• PNG
• SVG
• JPG
• GIF

The standard is completely flexible that means that it is allowed to use additional file formats, such as Flash. If in such situation, EPUB file requires to include an alternate rendering of that file in one of the above four supported file formats. This means that users can embed a movie in Epub file. However, the software creating the file should take one of the initial frames of the movie that is embed in JPEG image. A reader device such e-book reader, which cannot show movies instead it displays JPEG image.

Conclusion

EPUB eBook file format can be downloaded as well as borrowed to machine or mobile device. Users can enjoy their eBooks with the user’s favourite app or program on PC or mobile device. In the above discussion, we have discussed deep about what is ePub file format that makes easy for users to understand it deeply.